Some wave rotors compress gasses with generally unsteady shock or compression waves and allow the gasses to expand by expansion waves. Typical wave rotors include an inlet end plate, an outlet end plate spaced apart from the inlet end plate along a central axis of the wave rotor, and a rotor drum positioned therebetween. The inlet port (or aperture) in the inlet end plate directs a flow of gasses into rotor passages formed in the rotor drum. The rotor drum defines passages that compress the gasses as the rotor drum rotates about the central axis relative to the inlet end plate and the outlet end plate. The outlet port in the exit end plate directs the gasses out of the rotor drum. The compression waves within the rotor passages may cause pressure pulses to travel upstream within the inlet port. The exit gasses may exit the outlet end plate port with high pressure pulses traveling within the exit flow.